マウス海馬苔状線維終末からのBDNFの活動依存的放出

抄録

Hippocampal mossy fiber pathway contains the highest concentration of BDNF in the CNS. It has been suggested that BDNF in the mossy fiber pathway regulates granule cell morphology and susceptibility to temporal lobe seizures and that it also anterogradely regulates the synaptic plasticity. Recently it is shown that BDNF is localized to the giant mossy fiber boutons. Here we report that BDNF is released from the giant mossy fiber boutons by the activity-dependent manner. The sindvis virus vector containing a fusion protein constract of BDNF and GFP derivative, Venus, was made and stereotaxically injected in the dentate gyrus of mouse hippocampus (C57BL/6, P14-21). After 2-3 days, hippocampus was removed, sliced at 300 mm and observed under confocal microscopy. We found that BDNF-Venus fluorescence was accumulated in the large MF boutons. The fluorescence was decreased in intensity by the high-frequency stimulation of MF axons. This response depended on extracellular calcium, and disappeared by either removing extracellular calcium or treating with NEM. These observations would provide direct evidences that BDNF is released from the giant mossy fiber boutons through exocytosis. [Jpn J Physiol 55 Suppl:S152 (2005)]